Wales found their scoring touch to run in 11 tries against a spirited but outclassed Japan as they won their third Pool B match 72-18 at the Millennium Stadium.
Winger Shane Williams scored twice to take his try tally to 34 on his 50th appearance, moving into second place behind Gareth Thomas in Wales’ all-time scoring list.
The predicted try spree sets up Wales nicely for what promises to be a winner-takes-all final group game against Fiji in Nantes on September 29.
Coach Gareth Jenkins made 10 changes to the side which lost to Australia but it was old stagers Martyn Williams and Shane Williams who stole the show.
The Welsh were forced to overcome another worrying sluggish start but three tries in an 18-minute spell in the second quarter secured the bonus point before half-time and they cut loose in the second quarter.
The Japanese were no pushovers, though, and long-range tries from wingmen Kosuke Endo and Hirotoki Onozawa were just rewards for their endeavours, which ensured there would be no repeat of the 98-0 defeat the last time they met Wales in Cardiff three years ago.
Centre Shotaro Onishi, who was carried off on a stretcher midway through the second half, had given his side a 3-0 lead with an early penalty to briefly silence the 40,000 crowd.
Lock Alun-Wyn Jones supported a break from recalled winger Dafydd James to score the game’s first try on 10 minutes but they trailed 8-7 after 19 minutes when Endo finished off a spectacular length-of-the-field breakaway move.
A solo try from James Hook and others from Rhys Thomas and Kevin Morgan made it 29-11 at the break and a purple patch from scrum-half Michael Phillips early in the second half took the game away from the Cherry Blossoms.
He scored one try and created another for Shane Williams, who took his tally to 33 on his 50th appearance to draw level with Ieuan Evans in second place in the Welsh all-time scoring list.
Gareth Cooper scored straight from a scrum and then Martyn Williams went in for his brace before Shane Williams fittingly brought the curtain down on the try feast.
